<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 闰年
        function years() {
            let year = prompt('请输入年份');
            if ((year % 4 == 0) && (year % 100 != 0) || ((year % 100 == 0) && (year % 400 == 0))) {
                console.log(year + '年是闰年');
            } else {
                console.log(year + '年是闰年');
            }
        }
        years();
    </script>
</body>
</html>